Tag Archives: eczema

Two studies presented at the American College of Allergy, Asthma and Immunology (ACAAI) Annual Scientific Meeting show there may be even more reason to love your dog.

The first study shows babies born in a home with a dog during pregnancy receive protection from allergic eczema, though the protective effect goes down by age 10. A second study shows dogs may provide a protective effect against asthma, even in children allergic to dogs.

“Although eczema is commonly found in infants, many people don’t know there is a progression from eczema to food allergies to nasal allergies and asthma,” says allergist Gagandeep Cheema, MD, ACAAI member and lead author. “We wanted to know if there was a protective effect in having a dog that slowed down that progress.”

The study examined mother-child pairs exposed to a dog. “Exposure” was defined as keeping one or more dogs indoors for at least one hour daily. “We found a mother’s exposure to dogs before the birth of a child is significantly associated with lower risk of eczema by age 2 years, but this protective effect goes down at age 10,” says allergist Edward M. Zoratti, MD, ACAAI member and a study co-author.

In the second study, researchers examined the effects of two different types of dog exposure on children with asthma in Baltimore. The first type was the protein, or allergen, that affects children who are allergic to dogs. The second type were elements, such as bacteria, that a dog might carry. The researchers concluded that exposure to the elements that dogs carry may have a protective effect against asthma symptoms. But exposure to the allergen may result in more asthma symptoms among urban children with dog allergy.

“Among urban children with asthma who were allergic to dogs, spending time with a dog might be associated with two different effects,” says Po-Yang Tsou, MD, MPH, lead author. “There seems to be a protective effect on asthma of non-allergen dog-associated exposures, and a harmful effect of allergen exposure.” The researchers believe that a child’s contact with factors other than dog allergen, such as bacteria or other unknown factors, may provide the protective effect. “However, dog allergen exposure remains a major concern for kids who are allergic to dogs,” says Dr. Tsou.

People with dog allergy should work with their allergist to reduce exposure. ACAAI has additional tips for those with dog allergy who keep a dog in the home:

Keep your dog out of your bedroom and restrict it to only a few rooms. But know that keeping the dog in only one room will not limit the allergens to that room.

After you pet or hug your dog, wash your hands with soap and water.

High-efficiency particulate air (HEPA) cleaners that run continuously in a bedroom or living room can reduce allergen levels over time. Regular use of a high-efficiency vacuum cleaner or a central vacuum can also reduce allergen levels.

Giving your dog a bath at least once a week can reduce airborne dog allergen.

Abstract Title: Effect of Prenatal Dog Exposure on Eczema Development in Early and Late Childhood.Author: Gagandeep Cheema, MD

A novel gene associated with canine atopic dermatitis has been identified by a team of researchers led by professors Kerstin Lindblad-Toh, Uppsala University and Åke Hedhammar, SLU, Sweden. The gene encodes a protein called plakophilin 2, which is crucial for the formation and proper functioning of the skin structure, suggesting an aberrant skin barrier as a potential risk factor for atopic dermatitis.

Details appear in the open-access journal PLoS Genetics.

Atopic dermatitis (or eczema) is an inflammatory, relapsing non-contagious skin disease affecting about 3-10 percent of dogs. The skin of a patient with atopic dermatitis becomes easily irritated by various allergens such as certain types of food, pollens or house mites. Such irritation causes very strong itching which leads to scratching, redness and flaky skin that becomes vulnerable to bacterial and yeast infections.

Despite many scientific efforts, little has been known about the genetics of the disease. In their study, researchers from Uppsala University, SLU and Broad Institute, compared DNA samples from a large group of German shepherd dogs affected by atopic dermatitis with DNA coming from healthy dogs to reveal the specific DNA segment associated with the disease.

“With the help of pet owners, we have managed to collect a unique set of DNA samples from sick and healthy dogs which allowed us to gain insight into atopic dermatitis genetics,” said first author Katarina Tengvall, Uppsala University.

Purebred dogs such as German shepherds have been selected for specific physical features for several generations. Selection led to an inadvertent enrichment for disease-risk genes in certain breeds. Moreover, the resulting architecture of canine DNA makes it easier to pinpoint segments that carry these disease risk-genes. This helped the researchers to reveal the genetics of atopic dermatitis. They found a region associated with the atopic dermatitis containing the gene PKP-2, which encodes Plakophilin-2, a protein involved in the formation and maintaining of the proper skin structure.

“The finding that certain variants of the PKP-2 gene may increase the risk of developing the disease opens new possibilities in understanding the disease mechanism leading to atopic dermatitis,” continues Katarina Tengvall.

These findings will not only lead to better understanding of the disease, which may lead to better treatment strategies long term. It also opens up the possibilities of development of a genetic test for the disease.

“Our study suggests that plakophilin-2 and an intact skin barrier is important to avoid atopic dermatitis”, says senior author, Kerstin Lindblad-Toh, professor at Uppsala University and Director of SciLifeLab Uppsala. “Another gene involved in the skin barrier has recently been linked to human atopic dermatitis emphasizing the similarity between canine and human atopic dermatitis” said Kerstin Lindblad-Toh.